U.S. Pat. No. 7,085,065 discloses a conventional fluid lens assembly that includes a rigid sheet serving as a lens, first and second rings secured to the rigid sheet, and a membrane retained between the first and second rings. A liquid may fill a space between the membrane and the rigid sheet so as to vary the focus of the lens.
U.S. Pat. No. 8,414,121 discloses another conventional fluid lens assembly (see FIG. 1) that includes a rigid optical lens (not shown) made of glass or plastic, a flexible contoured membrane 1 stretched over an edge of the optical lens, and a fluid (not shown) filling a cavity between the optical lens and the membrane 11. The membrane 11 includes thickness contours 111 with each thickness contour being an area of differing thickness so as to reduce optical aberrations (mainly astigmatism) of the fluid lens assembly.
The membrane 11 disclosed in U.S. Pat. No. 8,414,121 is relatively complicate and difficult to manufacture.